Stethoscope



1931- D. E. MACKEY ET AL 1,789,762-

STETHOSCOPE Filed Sept. 10, 1928 ATTOR NEY Patented Jan. 20, 1931 UNITED STATES PATENT. OFFICE DUDLEY E. MACKEY, OF BLOOMFIELD, AND FREDERICK L. BLACK, OF .EAST ORANGE, NEW. JERSEY STETHOSCOPE Application filed September 10, 1928. Serial No. 305,028.

The object of this invention is to increase the sensitive ends of a stethoscope by the elimination from the diaphragm casing of vibrations from outside sources, by employing an inner flared tube, the walls of which facilitate the passage of the sound waves from the diaphragm chamber to the flexible tube leading to the branch tubes through which the specialist listens;

A further object is to provide a diaphragm chamber surrounded by concentric elements with an intervening air chamber effecting sound insulation.

\Vith the foregoing and other objects in view, the invention consists in the novel construction and arrangement of elements described, illustrated and claimed, it being understood that modifications may be made within the scope of the claim without departing from the spirit of the invention.

' In the drawings forming part of this application Figure 1 is a perspective view of the device including the casing carrying the diaphragm, the main flexible tube, and the branch tubes equipped with ear pieces.

Figure 2 is a longitudinal section through the housing or casing mounting the diaphragm and the inner tubular member by means of which the diaphragm chamber is protected.

Figure 3 is a section on line 33 of Figure 2. i

In Figure 1 the main flexible tube is designated 10, a Y connection is shown at 11 and branch tubes 12 and 13 are connected with said device 11 and'carry ear pieces 14 of any standard type.

The diaphragm casing 15 may be of about the proportions illustrated, and it includes a cylindrical portion 15, a tapered portion 16 and an extension 17. Portion 15 is threaded at its outer end and accommodates the flanged ring 18 bymeans of which the dia .1 phragm 19 is held in position. Said porthe tube convenientlyabutting the shoulder formed by the end of element 17. The inner element further includes the cylindrical portion 24 and the portion 25 havingtapered.

walls by means of which the sound waves are conveyed without distortion or obstruction and passed through the space or chamber just within the diaphragm and through portion 22 and tube 10, and thence to the branch tubes and the rear pieces 14.

The flange 20 serves to separate the cylindrical portion 2-1 from portion 15, and an annular chamber 27 is provided which constitutes a sound insulation chamber,the tubular member 22 being concentric with and of the same exterior diameter as the interior wallsof element 17, this element 22 in conjunction with the fiange 20, serves to space the inner element as illustrated, and as required in order to carry out the purpose of the invention. The elements 15 and 24 may be, and usually are, of metal, and the tubular member mounted within the casing 15, notwithstanding its simple construction, has been found in practice to greatly facilitate the work of the specialist who employs an instrument of this character, for well known purposes.

Having described the invention what is claimed is:

A stethoscope, comprising an outer casing, a diaphragm, means connecting the diaphragm with the outer end of the casing, and a tubular member of less diameter than the casing and positioned in spaced relation therein, said tubular member opening toward the diaphragm and including a reduced extension and an intermediate portion, gradually decreasing in diameter and facilitating the direct passage of sound Waves Without distortion, from the diaphragm through the extension, said casing including an internal flange having an opening providing a all 5 engaged by the adjacent end portion of the tubular member, and closing the space be tween the casing and tubular member, at a point near the end of the casing.

In testimony whereof We affix our sigw natures.

- DUDLEY E. MACKEY.

FREDERICK L. BLACK. 

